A device intended to be implanted between two adjacent lumbar spinous processes during a minimally-invasive procedure to decompress neural structures, typically to treat a patient with symptomatic degenerative lumbar spinal stenosis (DLSS). It is typically designed as a small spacer, either a single-piece or assembly, made of metal [e.g., titanium (Ti), nickel-titanium alloy (Nitinol)] and/or synthetic polymer [e.g., hydrogel, polyetheretherketone (PEEK)]. Disposable devices associated with implantation (e.g., introducer needles, trocars) may be included with the device.